Not compatible with fastify-swagger

[vunamhung]

Hello,
Thank you for nice plugin, I use it and it work fine with normal request, but it not work with fastify-swagger request.

This is bug

Converting circular structure to JSON
    --> starting at object with constructor 'Socket'
    |     property 'parser' -> object with constructor 'HTTPParser'
    --- property 'socket' closes the circle

It's better if you can have a option to exclude some routes.

[codeaholicguy]

It's such a nice idea @vunamhung, a PR is always welcome, we will discuss in the PR for the implementation detail.